Unintentional overdose deaths increased 173% among U.S. adults between 1999 and 2010. This change is mostly due to increases in fatal opioid pain medication overdoses, which now greatly exceed deaths due to heroin overdose. For those with substance use disorders (SUDs), overdose is a leading cause of death, and the period after treatment for SUDs is high risk for overdose. Non-medical use of opioids is common among individuals with SUDs. Despite this, there are few interventions to reduce opioid medication overdose risk for those in SUD treatment. This project will develop a three-session intervention to reduce overdose risk behavior among individuals in SUD treatment with recent non-medical opioid use. The content will focus on opioid medication overdoses specifically, and will be based on: (a) motivational enhancement, which has been found to reduce risky alcohol use, and (b) overdose witness interventions, which have been used to train heroin users on overdose response. The intervention will also incorporate content on reducing risk of HIV infection given the opportunity to reach individuals at elevated risk for HIV and the overlap in HIV and overdose risk behaviors (e.g., injecting opioid medications and other drugs). After refining intervention content, a pilot randomized controlled trial will provide the preliminary dat needed to inform the design of a future large-scale evaluation of the efficacy of the intervention. Specifically, 60 men and 60 women will be randomized to the intervention or an attention control condition. Assessments will be conducted at baseline, at the completion of intervention/control procedures, and three and six months later. The specific aims are to: (1) refine a motivational enhancement prevention intervention for prescription opioid overdose risk reduction and improved witnessed overdose response for at-risk patients in addictions treatment; (2) conduct a pilot randomized controlled trial comparing the prescription opioid overdose prevention intervention to a supportive educational control condition for patients in addictions treatment in order to: (a) obtain information about the feasibility of randomized controlled procedures; and (b) determine the distribution and variability of the primary (overdose risk behaviors) and mediating/secondary (witnessed overdose response, self-efficacy to reduce overdose risk, knowledge of overdose risk factors and symptom recognition) outcomes; and (3) determine the distribution and variability in changes in HIV risk behaviors (e.g., reductions in injection of prescription opioids) over follow-up. A secondary aim of the proposal is to examine the variation in outcomes within sub-groups of participants defined by group (intervention vs. control) and gender. This study will provide crucial initial data on an innovative new strategy to prevent prescription opioid overdoses. The project will also provide initial data on the potential for integrating overdose and HIV prevention. The public health significance of this project is amplified by the combining of strategies to reduce participants' overdose risk with strategies to improve survival for individuals who overdose in the presence of participants.